Current communication devices, particularly mobile radio devices, have an input device for inputting text character by character into the communication device, the text consisting of a sequence of characters. The communication devices usually have a memory device for storing a plurality of reference character sequences, the reference character sequences of characters comprising various words, in the manner of a dictionary, which are input relatively frequently. The communication device is capable of comparing individual ones of the characters input in succession with the reference character sequences of characters by means of a prediction device. As soon as the prediction device determines one or more of the reference character sequences with matching sequence of beginning characters to the input characters during the comparison, the prediction device proposes the corresponding reference character sequences so that the user of the communication device, in the case of a relevant proposal, no longer needs to input all of the further individual characters of the sequence of characters to be input but, instead, can select the corresponding proposal. After the complete text of usually a number of words has been input, the text is transmitted via a conventional interface of the communication device and, as a rule, via intermediate network facilities to a remote communication device of a third party and is there displayed after reception.
In a mobile radio device, the numerical keypad is normally used as input device, a number of letters and possibly special characters being allocated to each number. Modern mobile radio devices have as an alternative or additional input device a sensitive, mostly touch-sensitive, interactive display device. The display device is used, for example, for displaying a virtual keypad with letters as in the case of a computer keyboard. Individual ones of the letters displayed can be selected with the aid of a pen whereupon the letters selected are temporarily stored as current text input as input characters in a memory device of the mobile radio device. Furthermore, interactive input devices are known which have a surface on which it is possible to write with a pen. The written letters are converted into the letter code of the communication device with the aid of a method for character recognition and temporarily stored as the input characters of the text.
Such a text input via a keypad or with a pen on an interactive input and/or display device on mobile radio devices is slow and fatiguing because, for example, words used more frequently have to be input time and again in detail via character recognition or virtual keypads. Fatigue and impatience of the user occur especially with repeated inputting of text. For example, short messages according to SMS (Short Message Service) with questions “where are you?” or “when will we meet?” are frequently input. Apart from the need to be able to recognize individual words in a simple and efficient manner with the aid of a prediction device, such complex sentence structures must be input completely word for word, the prediction methods of the prediction device frequently requiring a multiplicity of characters to be input before an individual one of the words is proposed correctly. In such prediction methods, the cognitive load on the user during the selection from a list of proposals is also relatively high and tends to distract from the actual writing of words. In addition, the fewer the letters of the word that have been input, the higher the number of proposals with variants of reference character sequences with identical first input characters. It has been found that many users prefer to enter individual letters before having to continuously change to and fro between the input of the individual characters and the selection of a prediction.
Apart from the possibility of entering text via such an input device where text is input successively character by character, search machines are known from the field of computer databases, in which the search terms can be input by using dummy characters. For example, the character sequence “*br*n*” can be input with “*” as dummy character in order to have all words displayed which first contain the character sequence “br” at any position within the character sequence and then contain the character “n” at any subsequent position.